1. Field of the Invention
The present invention relates to a data display unit mounted on a bicycle by which running data such as the running speed, the running time, the running distance etc. of a bicycle are calculated and displayed.
Particularly, the present invention relates to an improvement in the manner of display in a data display unit for a bicycle in which a microcomputer is incorporated to process the input data supplied from a sensor so that determined data such as the running speed etc. may be displayed.
2. Description of the Prior Art
A data display unit for a bicycle for making display of running data such as the running speed, the running distance and the like generally comprises a revolution detecting sensor for detecting the number of revolutions of a wheel and a main body of the display unit for calculating the running speed, the running distance and the like based on a signal from the revolution detecting sensor.
A revolution detecting sensor in general was, in the past, connected to a main body of a display unit by a release wire and the like so that a rotating block provided in the sensor may be mechanically rotated directly by the wheels. However, recently, in order that load may not be applied to a driving system of a bicycle and that the the number of revolutions may be detected more accurately, a so-called magnet sensor or a photoelectronic sensor has been utilized as a revolution detecting sensor.
In the U.S. Pat. No. 4,074,196 for example, it is disclosed that a sensor comprising a photoelectronic sensor, a magnetic sensor or a Hall device can be utilized as a revolution detecting sensor. The U.S. Pat. No. 4,156,190 discloses an example of a photosensor as a revolution detecting sensor. These revolution detecting sensors are attached in association with the wheels.
A main body of a display unit having close relation with the present invention is disclosed for example in the U.S. Pat. No. 4,007,419 which comprises a calculating the running speed, the running distance and the like based on a revolution signal provided from a revolution detecting sensor and also comprises liquid crystal display for indicating the running speed, the running distance and the like. Such a main body of a data display unit is mounted on a desired position near the handle or any other suitable position where the rider of the bicycle can easily see the display.
In such a conventional data display unit for a bicycle as described above, the running distance and other data to be displayed are generally not calculated at all times and selection can be made for stop of the calculation or for start of the calculation. In this case, if the running distance for example is displayed in a conventional data display unit, it is only by the incrementation in the display of the running distance that the rider of the bicycle can ascertain whether the running distance displayed is the data being calculated or the data in the stop state of calculation.
However, if the bicycle runs slowly, incrementation in the display of the data display unit is made very slowly (for example, incrementation in the display is not made till the bicycle runs for 10 m in case the display data changes for every 10 m) and accordingly, such a conventional display unit has a disadvantage that the rider of the bicycle cannot immediately know whether the running distance is being calculated or not. In addition, when the bicycle is stopped, he cannot know whether the running distance is being calculated or not since the data of the running distance is not incremented. If data other than the running distance, for example, the total distance or the present time is selectively displayed, he cannot either know whether the running distance is being calculated or not since the running distance is not displayed.